Blackwater Fever: Divine Retribution Or Genetic Happenstance?
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Blackwater Fever: Divine Retribution or Genetic Happenstance? Imagine a remote tribe, say in sub-Saharan Africa, 700 years ply of tropical afflictions; and they too were bitten by malaria- ago. Its population of about 4,000 survives on a rice-based, bearing mosquitoes. But the native population, having lived agrarian economy. Their excess harvests are periodically traded with the menace of malaria for a hundred generations, had with neighboring clans to augment the variety of their diet inherited a modest measure of resistance to the disease; not so and to provide additional household needs. Other than rare with the white slavers, their soldiers, missionaries or adventur- exogamous marriages, there is virtually no immigration or emi- ers seeking precious metals. gration; hence the tribal population, except for intervals of in- The medical literature of 1830 carried an article by a ter-tribal warfare, gradually increases as the yearly births gen- French naval officer noting an allegedly new disease in East erally outnumber the deaths. Africa. This illness began suddenly, with high fever, shaking What medical problems might this tribe encounter? As chills, marked asthenia, rapid pulse, bilious vomiting, obvious with any sub-Saharan community, they will certainly be bur- jaundice, and, within days, a progressive darkening of the urine. dened by a full range of parasitic diseases generally insect-borne. This disease, called blackwater fever, was originally con- Most of the residents will have been beset with malaria, as well fused with yellow fever or some sort of morbidity affecting the as a variety of parasitic worms, and, from childhood, a host of liver. Certainly the jaundice, the bile-stained vomitus and the other parasitic afflictions. darkened urine collectively pointed toward a disease of the liver. Survival was necessarily precarious, with high mortality Only belatedly was it recognized as a complication of malaria. rates particularly in childhood; but over the many generations, As more and more of these cases were recognized in cen- certain members of the tribe, endowed with variant genetic tral Africa – and later, in India and China – it became appar- traits, overcame diseases such as malaria; they did not avoid ent that the acute breakdown of red blood cells was the cata- these pestilences but rather, through genetically-enhanced re- strophic event leading to free hemoglobin and fragmented red sistance, managed to survive in an unremittingly hostile envi- blood cells clogging the kidneys and discoloring the urine. And ronment. Thus, generation by generation – empowered by further, that this was not a new disease but rather a severe com- the remorseless darwinian axiom that proclaims survival be plication in a patient already burdened by the most serious granted to the fittest – an increasing number of the tribal citi- form of falciparum malaria. zenry became endowed with those inheritable traits that in- Blackwater fever, strangely, was largely confined to creased systemic resistance to certain diseases. Europeaners dwelling in malarial Africa, especially blonds from These genetic traits did not prevent these diseases; they northern Europe. Was this divine retribution for the Euro- merely converted them from an acute, often lethal infection, pean rape of the African continent? Or was it the process of to milder, lingering disorders. natural selection which had so altered the genetic profile of The African continent, however, could not quell the in- resident Africans to make them slightly more resistant to the terest or avarice of those living to its north or northeast. Arabic secondary ravages of the malignant form of malaria? trading posts were established along the African east coast by In 1942, just months after this nation’s entrance into a the 13th Century. And Dar es Salaam, now a thriving city of global war beyond our boundaries, the United States Army some 2.5 million Tanzanians, was already a commercial site over issued a lengthy bulletin describing the hazards of blackwater eight centuries ago. fostering limited trade with the African fever, ending with this sentence: “Recurrence of blackwater interior including slavery. By 1415 the Portuguese had estab- fever is common, especially in the tropics. Send patient to tem- lished a small European foothold in northern Africa. And by perate zone if possible.” 1434 Portuguese mariners had reached Cape Bojador (lati- tude 26 degrees north) and by 1441 had begun to capture – STANLEY M. ARONSON, MD Africans for slavery. In 1494, two years after Columbus’s initial voyage to the West, Spain and Portugal signed the infamous Stanley M. Aronson, MD is dean of medicine emeritus, Treaty of Tordesillas dividing the non-Christian world between Brown University. these two nations. The other west European nations, also seek- Disclosure of Financial Interests ing African colonies, ignored the treaty. Stanley M. Aronson, MD, and spouse/significant other have What has this to do with that hypothetical village of 4,000 no financial interests to disclose. native Africans? Sooner or later, European colonists ventured beyond their coastal strongholds to plunge into the continen- CORRESPONDENCE tal interior for purposes as varied as missionary conversion, com- e-mail: [email protected] merce or the capture of slaves. And sooner or later, with Europeaners dwelling in the same environment as the indigenous Africans, these latecomers to the continental interior were confronted with the same pano- 259 VOLUME 93 NO. 9 SEMPTEMBER 2010.